JP4479746B2 - Method for evaluating emulsified composition - Google Patents

Description

The present invention relates to a method for evaluating an emulsion composition.

  Emulsions are used in a wide range of technical fields such as foods, cosmetics, pharmaceuticals, building materials and paints. Since emulsification is uniformly dispersed in a medium in which one of water and oil, which are not originally mixed, is made into fine droplets and the other is made into a continuous phase, various techniques are available for improving the stability over time of emulsification and ease of use. It is highly desired in the field. Especially for cosmetics / pharmaceuticals that may be used in contact with the human mucous membrane or skin, and foods to be taken orally, there is a demand for an emulsifier that is safe, less irritating, has high emulsifying ability, and is easy to use. Yes.

  However, the fact is that conventional emulsifiers do not always satisfy such requirements. For example, nonionic surfactants such as glycerin fatty acid esters and polyoxyethylene alkylene ethers are safe and gentle to the human body but may lack deficiency in emulsifying capacity, while fatty acid soaps, ether carboxylic acids and their salts The ionic surfactants such as alkane sulfonate, dialkylsulfosuccinic acid, higher alcohol, alkylamine acid, and alkanolamine fatty acid derivatives have high emulsifying ability but have problems in safety and mildness to the human body.

  Under such circumstances, various attempts have been made to satisfy a wide range of safety, mildness, emulsification ability and the like by blending a plurality of emulsifiers. For example, in Patent Document 1 (Japanese Patent Laid-Open No. 5-246821) and Patent Document 2 (Japanese Patent Laid-Open No. 7-25724), a coating film is formed by combining an ionic surfactant represented by sucrose fatty acid diester and soap. An emulsion composition with high water resistance is obtained. In patent document 1 (Unexamined-Japanese-Patent No. 5-246821), the emulsion composition similarly high in water resistance is provided by combining polyglycerol fatty acid ester and fatty acid lactic acid ester salt.

  In addition, some attempts to improve the function by blending a plurality of emulsifiers in fields other than emulsification have been reported. Patent Document 3 (Japanese Patent Laid-Open No. 62-65646), Patent Document 4 (Japanese Patent Laid-Open No. 6-225684), Patent Document 5 (Japanese Patent Laid-Open No. 6-181701), Patent Document 6 (Japanese Patent Laid-Open No. 5-161446) In each publication, such as publications), the quality of flour foods and process improvements are improved by combining various food emulsifiers including sucrose fatty acid esters and fatty acid lactic acid ester salts, and other substances. In Patent Document 7 (Japanese Patent Laid-Open No. 7-173045), skin treatment characteristics are expressed by combining a coconut oil fatty acid sucrose ester and a fatty acid lactate ester salt. In patent document 8 (Unexamined-Japanese-Patent No. 5-316950), the sucrose fatty acid ester mixture which can be utilized suitably as frying oil was achieved by preparing the mixing mixture from which ester substitution degree differed.

However, these techniques are intended for specific systems such as coated cosmetics with high water repellency, and their use is limited to specific fields and lacks versatility. Further, in the prior art, nothing has been studied about the emulsifier purity and the blending ratio other than the above-mentioned Patent Document 8 (Japanese Patent Laid-Open No. 5-316950).
On the other hand, only the diester form of sucrose fatty acid ester is closed up, and several attempts to improve functions and develop applications using sucrose fatty acid ester having high diester purity have been reported [Patent Document 9 (Japanese Patent Laid-Open No. Hei 5-). No. 1090), Patent Document 1 (Japanese Patent Laid-Open No. 5-246821), etc.]. However, it is insufficient to obtain an emulsifier that is safe and highly dispersible and has an excellent emulsion stabilization effect.
Japanese Patent Laid-Open No. 5-246821 Japanese Patent Laid-Open No. 7-25724 JP-A 62-65646 JP-A-6-225684 JP-A-6-181701 JP-A-5-161446 JP 7-173045 A JP-A-5-316950 JP-A-5-1090

Under such circumstances, the present invention is versatile, safe, gentle to the human body, easy to disperse, no unnecessary foaming at the time of homogenization, and more excellent in emulsion stabilization effect. The object of the present invention is to provide a novel method for evaluating an emulsified composition from which the composition can be selected.

As a result of repeated studies on the disintegration pressure of the emulsified composition in order to achieve the above object, it was found that the emulsification function depends on the interfacial alignment of the emulsifier, and the emulsifier compounding ratio, particularly the degree of ester substitution of sucrose fatty acid esters, is greatly affected. It turns out that it affects. Among them, a sucrose fatty acid ester having an triester content of 30% by weight or more, especially an average degree of esterification of 1.6 to 2.9, and an ionic surfactant are used in combination at a specific ratio. The emulsion composition has a high appearance, no irritation to the human body, excellent emulsification stability, excellent dispersibility in oil or water, and no appearance of unnecessary foaming during homogenization. . Moreover, based on these results, it discovered that the disintegration pressure of an emulsion composition could be used for evaluation of emulsification ability, and came to complete this invention.
That is, according to the present invention, the following evaluation methods for emulsion compositions (1) to ( 5 ) are provided.
(1) Measure the disintegration pressure of the emulsified composition represented by the surface pressure value when the solid film disintegrates on the π-A isotherm obtained when the emulsified composition is spread on the water surface and compressed from the outside. And the evaluation method of an emulsion composition characterized by determining the emulsification performance of an emulsion composition based on the measured value.
( 2 ) The evaluation method according to (1) above, wherein when the collapse pressure is in the range of 50 to 58 mN / m, it is determined that the emulsion composition has a preferable emulsification performance.
( 3 ) Furthermore , the π-A isotherm obtained when the emulsified composition is spread on the water surface and compressed from the outside, and is represented by the area value when the range showing the solid film is extrapolated to π = 0. The method according to (1) or (2) , wherein the molecular occupation area of the emulsion composition is measured simultaneously with the collapse pressure, and the emulsification performance of the emulsion composition is determined based on the measured values. .
( 4 ) When the collapse pressure is 50 to 51 mN / m and the molecular occupation area is 1.25 to 1.35 nm ² / mol, it is determined that the emulsion composition has preferable emulsification performance. The evaluation method according to (3) above .
( 5 ) When the collapse pressure is 55 to 58 mN / m and the molecular occupation area is 0.87 to 1.00 nm ² / mol, it is determined that the emulsion composition has preferable emulsification performance. The evaluation method according to (3) above .

By using the evaluation method of the present invention, it is possible to select an emulsion having high safety, no irritation to the human body, and excellent stability. In addition, the emulsion has high dispersibility in oil or water, and is excellent in convenience without unnecessary foaming at the time of homogenization, coloring or odor to the product.
Moreover, the emulsion selected using the evaluation method of the present invention has high safety, is mild, has excellent emulsion stability, and is suitably used for foods, cosmetics and the like.

Hereinafter, the present invention will be described in detail.
As the fatty acid constituting the sucrose fatty acid ester used in the present invention, a fatty acid having 12 to 22, preferably 12 to 18, more preferably 16 to 18 carbon atoms is used. If the fatty acid chain length is shorter than this range, the affinity of the lipophilic part to the oil is weak, so that the emulsification stability is deteriorated, and significant foaming may occur during emulsification, which is not preferable. Further, even if the fatty acid chain length is longer than this range, the crystallinity of the emulsifier itself is too high, and the lipophilic part becomes less compatible with the oil, and the emulsion stability becomes poor as in the case where it is too short. Moreover, it is not preferable because it is difficult to obtain raw materials.

  Fatty acids may be saturated or unsaturated within the above carbon number range, and may be linear or branched. In the case of a branched chain, the length of the longest chain is preferably 8 or more, more preferably 10 or more. In some cases, it may be a hydroxyl carboxylic acid having a hydroxyl group. These fatty acids include myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, tetradecenoic acid, hexadecenoic acid, octadecenoic acid (such as oleic acid and elaidic acid), octadecadienoic acid (such as linoleic acid), and octadecaic acid. Trienoic acid (such as linolenic acid), eicosenoic acid, eicosatetraenoic acid (arachidonic acid), docosenoic acid (erucic acid), isostearic acid, hexyldecanoic acid, hexylundecanoic acid, octyldecanoic acid, hydroxytetradecanoic acid, hydroxyhexadecanoic acid, And hydroxyoctadecanoic acid.

Of these, palmitic acid, stearic acid, and the like are preferable because they have excellent emulsifying performance and are easily available, and it is particularly preferable to use stearic acid in an amount of 70% by weight or more.
In the present invention, among the sucrose fatty acid esters, the triester content is 30% by weight or more, preferably 50% by weight or more. When the triester content is 30% by weight or less, the collapse pressure decreases and the area occupied by the molecule increases. That is, it is not preferable because the viscosity after emulsification becomes low and the storage stability after emulsification deteriorates.

  The sucrose fatty acid ester used in the present invention preferably has a molar average esterification degree of 1.6 to 2.9. The molar average esterification degree represents the molar average esterification degree of the sucrose fatty acid ester. For example, when the purity is 100%, it is 1 for a monoester and 2 for a diester. In the case of a mixture, if the weight ratio is monoester / diester = 50/50, the molar average esterification degree is (1 × 50 / M1 + 2 × 50, where M1 is the molecular weight of the monoester and M2 is the molecular weight of the diester. / M2) / (50 / M1 + 50 / M2) If the molar average esterification degree is less than 1.6, the surface area of the hydrophilic part is larger than that of the hydrophobic part, and the emulsification increases the curvature of the oil / water interface. Is not preferable. On the other hand, if it exceeds 2.9, the surface area of the hydrophilic part is smaller than that of the hydrophobic part.

  Such sucrose fatty acid esters form an emulsified composition with an ionic surfactant. The ionic surfactant is not particularly limited, and both anionic and cationic can be used. Specifically, long chain aliphatic carboxylic acid lactic acid ester salt, aliphatic metal salt (soap), alkane sulfonate, alkylbenzene sulfonate, higher alcohol fatty acid salt, dialkyl sulfosuccinate, organic as anionic surfactant Examples thereof include acid monoglyceride salts, and examples of cationic surfactants include alkylamine salts, alkylammonium salts, and alkylpyridinium salts. In the present invention, an anionic surfactant is preferably used, and particularly a fatty acid lactic acid ester or a salt thereof is preferably used. In the fatty acid lactic acid ester or a salt thereof, these fatty acids may be a mixture of two or more of any ratio. As the fatty acid constituting the fatty acid lactic acid ester, the same fatty acid as the fatty acid constituting the aforementioned “sucrose fatty acid ester” is used.

The lactic acid in the fatty acid lactic acid ester salt may be produced by either a fermentation method or a synthesis method, and it does not matter whether the D-form or L-form is distinguished.
A method for obtaining a fatty acid lactic acid ester or a salt thereof having a purity of 80 mol% or more is not particularly limited, and any method may be used. An example is a method of purifying a reaction product by a known production method by some means.
In this invention, this sucrose fatty acid ester and ionic surfactant are mixed in arbitrary ratios, and an emulsion composition is obtained. Preferably, the ionic surfactant is 0.05 to 30% by weight with respect to 70 to 99.95% by weight of the sucrose fatty acid ester.

  The emulsified composition of the present invention preferably has a collapse pressure of 50 to 58 mN / m, which is a measure representing the strength of the membrane when compressed. The collapse pressure is a π-A isotherm obtained when the emulsified composition is developed on the water surface and compressed from the outside at 10% / min, and is represented by the surface pressure value when the solid film collapses. In general, when the membrane is weak, the collapse pressure is low, and when the membrane is strong, the collapse pressure is high. However, the stronger the film, the less flexible and the harder the film. Therefore, a somewhat strong and supple (not too hard) film has high alignment at the oil / water interface and high emulsifying ability. That is, when the collapse pressure is less than 50 mN / m, the membrane is weak, and when it exceeds 58 mN / m, the membrane becomes strong, but it is too hard and the emulsifying ability is lowered.

A more preferable emulsion composition of the present invention has a molar average esterification degree of sucrose fatty acid ester of 1.67 to 1.74, and an emulsification composition using the emulsion composition has a disintegration pressure of 50 to 51 mN / m, and 1 The area occupied by the molecule representing the area of the hydrophilic portion of the surfactant per molecule is 1.25 to 1.35 nm ² / mol.
In another preferred emulsion composition of the present invention, the molar average esterification degree of sucrose fatty acid ester is 2.42 to 2.72, and the disintegration pressure of the emulsion composition using the same is 55 to 58 mN / m, The molecular occupation area representing the area of the hydrophilic part of the surfactant per molecule is 0.87 to 1.00 nm ² / mol.

  In addition to this, an arbitrary component may be selected and added to the emulsified composition of the present invention from among additive components commonly used in ordinary emulsification systems within the range where the object of the present invention is not impaired. Examples of such additive components include polyglycerin fatty acid ester, monoglyceride, organic acid monoglyceride, sorbitan fatty acid ester, lecithin, sodium polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene Highly safe surfactants such as sorbitan fatty acid ester, fatty acid alkanolamide, carboxybetaine type, imidazolinium type, sulfobetaine type, amino acid surfactant, and carrageenan, locust bean gum, guar gum, tamarind gum, Arabia Natural thickening stabilizer such as gum, xanthan gum, pectin, pullulan, casein, gelatin, albumin, casein, soy protein, gluten, etc. Cellulose, sodium casein, synthetic thickening stabilizer such as polyacrylic acid, more flavors, sweeteners, flavorings, colorants, humectants, disinfectants, enzymes, and the like anti-inflammatory agents.

The emulsified composition can be used as an emulsifier for foods, cosmetics and the like. The form at this time is influenced mainly by the melting point of the fatty acid lactic acid ester salt and sucrose fatty acid ester used, and is often solid, but depending on the fatty acid species and the added components, it can be liquid or basto. .
Next, the emulsion using this emulsion composition is demonstrated. The form of emulsification (oil-in-water type, multiple emulsification, microemulsion, etc.) is appropriately selected, but the emulsified composition is particularly suitable for an oil-in-water type emulsion.

There is no restriction | limiting in particular as an aqueous component, Water and various aqueous solution are mention | raise | lifted. In this aqueous component, various water-soluble components blended in ordinary foods, cosmetics and the like, for example, saccharides, alcohols, salts such as sodium chloride and potassium carbonate, and the like can be blended.
The oil component is not particularly limited, and includes animal and plant derived fats and oils, mineral derived fats and oils, and chemically synthesized products. Specifically, soybean oil, cottonseed oil, rapeseed oil, palm oil, palm oil, sesame oil, castor oil, cacao butter, safflower oil, olive oil, beef tallow, pork fat, fish oil, whale oil, butterfat, and hydrogenated products thereof Processed oils and fats such as transesterified oil, waxes such as wood wax, beeswax and sheep wax, sterols such as lanolin and cholesterol, paraffins such as liquid paraffin, hydrocarbons such as petroleum jelly and squalane, palmitic acid, And higher fatty acids such as stearic acid, higher aliphatic alcohols such as cetanol and stearyl alcohol, and esters such as diethyl phthalate, dibutyl phthalate and cholesterol isostearate. These oil components can further contain an antioxidant, an oil-soluble drug, and the like. In addition, the oil component may be used alone or as appropriate.

The content of fats and oils in the emulsion is not particularly limited, but is preferably 2 to 90% by weight.
The suitable usage-amount of an emulsion composition is 0.01 to 60 weight% with respect to the whole emulsion, Preferably it is 0.01 to 20 weight%, More preferably, it is 0.1 to 5 weight%. If the amount used is smaller than this, sufficient stability cannot be obtained. On the other hand, if it is used in excess of this amount, the emulsifying effect will not be remarkably improved, and unnecessary thickening may be caused. Is also disadvantageous.

  The emulsification method is not particularly limited, but examples thereof include the following method. That is, the present emulsifier composition and water are heated and stirred at a temperature equal to or higher than the Kraft point of the emulsifier composition, and a method of homogenizing the oil component, or the oil-soluble component of the emulsifier composition. Examples thereof include a method of homogenizing an oily component obtained by dissolving components by heating and water in which a predetermined amount of a basic substance is dissolved in advance.

EXAMPLES Hereinafter, although an Example demonstrates this invention still in detail, this invention is not limited to a following example, unless the summary is exceeded.
<Examples and comparative examples>
Tables 1 to 4 show the results of preparing emulsifiers containing fatty acid lactic acid ester salts and sucrose fatty acid esters, emulsifying them, and evaluating them.

The emulsifier composition was evaluated as follows.
1. Creaming rate of emulsified composition (ml / hr): The amount of water separation 1 hour after the emulsification was taken as the initial creaming rate.
2. Molecular Occupied Area of Emulsified Composition (nm ² ): π-A isotherm obtained when the emulsified composition is spread on the water surface and compressed at 10% / min from the outside, and the range showing the solid film is π = Area value when extrapolated to zero.
3. Disintegration pressure (mN / m) of the emulsified composition: The surface when the solid film disintegrates on the π-A isotherm obtained when the emulsified composition is spread on the water surface and compressed from the outside at 10% / min. Pressure value.
4). Emulsion stability: Ratio when the amount of water separation (ml) of an emulsion stored at 25 ° C. for 24 hours after production was measured and divided by the total amount.
The emulsification was a system to which 4 mol% of lactate stearate was added, and the molar average esterification degree of lactate stearate was 1.

<Method for producing oil-in-water emulsion>
The emulsified composition was dispersed in water at 25 ° C., soybean oil or liquid paraffin was added, and the mixture was heated to 60-80 ° C. and stirred.
The aqueous phase and the oil phase were emulsified at 70 ° C. and 10,000 rpm for 5 minutes using an ace homomixer manufactured by Nippon Seiki Co., Ltd., and then rapidly cooled with ice water.

なお上記ショ糖脂肪酸エステルは、以下のエステル混合物である。

The sucrose fatty acid ester is the following ester mixture.

Claims (5)

Measure the disintegration pressure of the emulsified composition represented by the surface pressure value when the solid film disintegrates with the π-A isotherm obtained when the emulsified composition is spread on the water surface and compressed from the outside. An evaluation method of an emulsified composition, wherein the emulsification performance of the emulsified composition is determined based on a measured value.   The evaluation method according to claim 1, wherein when the collapse pressure is within a range of 50 to 58 mN / m, it is determined that the emulsion composition has a preferable emulsification performance. Furthermore , the emulsified composition represented by the area value when the range showing the solid film is extrapolated to π = 0 in the π-A isotherm obtained when the emulsified composition is spread on the water surface and compressed from the outside. The evaluation method according to claim 1 or 2, wherein the molecular occupation area of the product is measured simultaneously with the collapse pressure, and the emulsification performance of the emulsified composition is determined based on the measured values. When the collapse pressure is 50 to 51 mN / m and the molecular occupation area is 1.25 to 1.35 nm ² / mol, it is determined that the emulsion composition has preferable emulsification performance. Item 4. The evaluation method according to Item 3. When the collapse pressure is 55 to 58 mN / m and the molecular occupation area is 0.87 to 1.00 nm ² / mol, it is determined that the emulsified composition has a preferable emulsifying performance. Item 4. The evaluation method according to Item 3.